Mounting of rotary split slitting knives

ABSTRACT

A split rotary slitting knife removably mounted to a split annular head is positioned so that the diametrically opposed joints between head portions are angularly offset from the joints where the cutting portions of the blade sections abut. The ends of each of the blade sections extend across both of the head joints for proper alignment of the blade sections.

United States Patent Saunders Nov. 26, 1974 [54] MOUNTING OF ROTARYSPLIT SLITTING 3,246,555 4/1966 Finlay 83/665 KNIVES 3,541,656 11/1970Devon 83/698 X [75] Inventor: Lawrence J. Saunders, Elmont, N.Y. P E W11G Ab b rtmary xammer 1 1e ercrom 1e [73] Asslgnee: S & Scorrugmed Paper& Attorney, Agent, or FirmOstrolenk, Faber, Gerb &

Machinery Co., Inc., Brooklyn, NY. soffen [22] Filed: Jan. 21, 1974 [21]Appl. No.: 435,336 57] ABSTRACT A split rotary slitting knife removablymounted to a [52] us Cl 83/665 83/675 6 split. annular head ispositioned so that the diametri- [51] Int Cl B26d 1/12 823d 35/00 callyopposed joints between head portions are angu- [58] i 83/663 & 665 675larly offset from the joints where the cutting portions g of the bladesections abut. The ends of each of the blade sections extend across bothof the head joints [56] References Cited for proper alignment of theblade sections.

UNITED STATES PATENTS Antosh 83/675 x 6 Claims, 4 Drawing FiguresMOUNTING OF ROTARY SPLIT SLITTING KNIVES This invention relates toknives in general and more particularly relates to rotary knives forlongitudinally slitting web material.

In the production of double-faced corrugated board, a corrugated websandwiched between two flat liner webs is bonded thereto to form arelatively stiff composite web, typically from 85 inches to 105 incheswide. The composite web passes through slitting apparatus which includessets of opposed cooperating annular knives transversely positioned totrim the edges of the relatively wide web and also slit the weblongitudinally into two or more relatively narrow composite webs thatare fed to a cutoff means which transversely cuts the relatively narrowwebs into sheets of corrugated board.

Since the slitter blades must be repositioned very often, each annularblade is split and is mounted to a split annular head which is clampedto a drive shaft in a manner which permits the clamping forces to berelaxed so that the head with the blade thereon may be transverselypositioned with respect to the longitudinal axis of the web to be cut.Relatively rapid wear of the blade requires that it be split tofacilitate changing thereof.

In accordance with the prior art, the two splits in the annular bladeare aligned with the splits in the head. Unfortunately, this permitsmisalignment between the cooperating head sections of the annular blade,and because of the engagement between cooperating knives, misalignedknife sections often chip thereby resulting in poor quality slitting andshortened life for the blade sections.

To significantly reduce, if not entirely eliminate, misalignment ofsplit knife sections, the instant invention provides a construction inwhich the joints between the split knife sections are angularly offsetwith respect to the joints between the split head sections. Further,each end of each blade section is constructed so that a portion thereofbridges a joint between sections of the split head. It appears thatbecause the blade splits and the head splits do not coincide, as they doin the prior art, there is improved alignment between slitting surfacesof the split knife sections.

Accordingly, a primary object of the instant invention is to provide animproved construction for a split annular knife mounted to a splitannular head.

Another object is to provide slitter knife sections mounted to splithead sections in a manner such that knife joints are angularly displacedfrom the head joints.

Still another object is to provide split knives and heads of this typein which portions at each end of each of the split knife sections extendacross a split at the boundary between head sections.

These objects as well as other objects of this invention will becomereadily apparent after reading the following description of theaccompanying drawings in which:

FIG. 1 is an exploded perspective of a split annular slitter blade andhead therefor.

FIG. 2 is a side elevation of the elements of FIG. 1 in assembledpositions.

FIG. 3 is a fragmentary cross-section taken in a plane extending throughthe diameters of an upper and lower slitter shaft.

FIG. 4 is a side elevation of a prior art slitter knife mounted to asplit annular head.

Now referring to the figures. A rotary slitter includes upper and lowerdriven shafts 11,12 mounting annular heads 13, 14, respectively, whichcarry the respective annular knives 15, 16. The board being slit travelsalong path P extending parallel to the longitudinal axes of shafts 11,12 and through the engaged cutting edge areas 17, 18 of the respectiveknives 15, 16. The web travels in a direction perpendicular to the planewherein the longitudinal axes of shafts ll, 12 are disposed.

Since heads 13, 14 are of identical construction and blades 15, 16 areof identical construction, for the sake of brevity only theconstructions of head 13 and blade 15 will be described in detail. Withparticular reference to FIGS. 1 and 2, it is seen that head 13 isconstructed ot two arcuate portions 21, 22, each in length, with theirends held in abutting relationship by clamping screws 23, 24 that passthrough clearance apertures (not shown) in head portion 21 that arereceived by threaded apertures 25, 26 in head portion 22 so that thesplits or joints 27, 28 where the ends of head portions 21, 22 abut arediametrically opposed. As is well known to the art, the tightening ofscrews 23, 24 clamp head 13 in a selected position along the length ofshaft 11. Tongue and groove means (not shown) may be provided in theabutting surfaces of head portions 21, 22.

Each of the head portions 21, 22 is provided with a plurality ofthreaded apertures 28 extending inward from their respective flatmounting surfaces 31, 32 respectively. Arcuate shoulders 33, 34 alongthe board boundaries of the respective subassemblies 31, 32 serve topartially position arcuate blade sections 35, 36 constituting splitblade 15. Screws 37 pass through clearance apertures 38 in blade section35, 36 and are received by apertures 28 to clamp blade section 35against head surface 31 and clamp blade section 36 against head section32. The ends of arcuate cutting edges 17 along the outer edges thereofat blade sections 35, 36 abut at joints 41, 42, respectively.

Blade section 35 includes extensions 43, 44 at opposite ends thereofwhich project across blade joints 41, 42 and extend across head joints27, 28. The ends of blade section 36 at the inner portions thereof areprovided with notches 45, 46 which receive the respective extensions 43,44, and end portions of blade section 36 bridge joints 27, 28. Thus,blade joints 41, 42 are angularly offset from head joints 27, 28.

The misalignment of blade joints 41, 42 with respect to head joints 27,28 and the constructions of blade sections 35, 36 so that the endsthereof extend across both head joints 27, 28 result inimprovedalignment between the cutting edges 17, 17 of blades sections 35, 36.This is in contrast to the prior art (FIG. 4) in which the joint 51between split blade sections 52, 53 is aligned with joint 54 betweensplit head portion 55, 56.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now become apparent tothose skilled in the art. Therefore, this invention is to be limandsecond arcuate sections having, respectively, first and second parts ofsaid cutting edge mated at the ends thereof at first and second bladejoints whereat the ends of the cuttingedge parts abut; said blade jointsbeing angularly displaced from said head joints; in the vicinity of eachof said blade joints one of said blade sections having an end projectionbridging the head joint adjacent thereto, and the other of said bladesections having an end notch to receive the end projection.

2. An assembly as set forth in claim 1 in which the head joints arelocated at diametrically opposed positions.

3. An assembly as set forth in claim 2 in which both of the endprojections are provided by said first section, and both of said notchesare provided by said second section.

4. An assembly as set forth in claim 2 in which the blade joints areboth positioned on the same side of a line extending between the headjoints.

5. An assembly as set forth in claim 4 in which both of the endprojections are provided by said first section, and both of said notchesare provided by said second section.

6. An assembly as set forth in claim 5 in which the blade abuts agenerally flat surface of the head.

1. An assembly including an annular head selectively mountable along the length of a drive shaft and an annular blade removably mounted to said head; said head including first and second separable arcuate portions mated at the ends thereof at first and second head joints; said blade including a circular cutting edge along the outer edge thereof; said blade also including first and second arcuate sections having, respectively, first and second parts of said cutting edge mated at tHe ends thereof at first and second blade joints whereat the ends of the cutting edge parts abut; said blade joints being angularly displaced from said head joints; in the vicinity of each of said blade joints one of said blade sections having an end projection bridging the head joint adjacent thereto, and the other of said blade sections having an end notch to receive the end projection.
 2. An assembly as set forth in claim 1 in which the head joints are located at diametrically opposed positions.
 3. An assembly as set forth in claim 2 in which both of the end projections are provided by said first section, and both of said notches are provided by said second section.
 4. An assembly as set forth in claim 2 in which the blade joints are both positioned on the same side of a line extending between the head joints.
 5. An assembly as set forth in claim 4 in which both of the end projections are provided by said first section, and both of said notches are provided by said second section.
 6. An assembly as set forth in claim 5 in which the blade abuts a generally flat surface of the head. 